In the previous article we discussed about theory behind the neuromuscular fatigue and muscle fatigue threshold (MFT). Now we present how easily the threshold can be detected with Myontec’s Mbody products. In addition, we introduce the exercise intensity zones based on MFT.
Endurance training intensities are classically categorized into exercise zones starting from light recovery intensity until maximal effort. Different exercise intensities mean different kinds of training adaptations to body. Light intensity training should dominate during base training season and should always be the foundation upon which everything else is based on. Light basic endurance training, modifies the body and its physiology so that it is able to use more oxygen and burn more fat as fuel. During long duration light intensity training the exercise technique is fine-tuned safely when during repeated and repeated cycles the nervous systems learns the correct activation patterns and therefore
movement efficiency increases. As unbelievable as it sounds, going slow helps to go faster for longer periods of time later during the season. Heart rate (HR) has been typically used to classify exercise zones. Heart rate reacts to the general state of cardio-respiratory system. Myontec Mbody offers an additional method to classify exercise intensities based on muscle loading (ML) and MFT, and
therefore based on neuromuscular function. As compared to HR, muscle loading represents more localised state of working muscles and therefore offers additional information about the training state. Muscle load reacts fast to changes in technique, environmental factors and muscle state (fatigue, tightness) and muscle load based training therefore helps to optimize training.
Myontec Mbody uses five training zones based on individual and sport specific MFT determination. Zone calculations are presented in figure 1.
Figure 1. Muscle Load (ML) based training zones. 100 % is ML corresponding to muscle fatigue threshold MFT.
Zone definitions and main use purposes are as follows:
ENDURANCE TESTS TO DETECT MFT
In order to be able to use ML based training zones, MFT has to be detected. We have developed several sport specific tests for that purpose. One of them, the General MFT Test, is a simplified test and therefore applicable for recreational use and multiple sports. In addition, for running and cycling we provide tests with discipline specific parameters that are commonly used in advanced testing protocols and in elite sports. Running test (“Incremental running test 6 x 1000 m”) is heart rate guided and cycling test (“Incremental cycling test until exhaustion”) is resistance/power guided to set and
maintain intensity stable throughout the intensity level. For all tests you need Mbody shorts and MCell connected to shorts as well as HR monitor (General MFT test and Incremental running test) or power meter / bike trainer (Incremental cycling test). Each test must be preceded by sufficient warm-up phase, because the muscles need to be adapted to their real “up-to-date” condition and
performance level. MFT calculation is done using Myontec’s Muscle Monitor software. Data generated by General MFT test and by Incremental running test need to be downloaded from MCell
to Muscle Monitor whereas Incremental cycling test data can be stored real time into Muscle Monitor. All the analysis, MFT determination as well as zones, are then analyzed automatically. We are also planning to launch the tests in future to the Mbody Live mobile software with on-line help instructions and timers.
General MFT test
General MFT test is easy heart rate guided exercise test applicable for every person and for many sport types to estimate MFT and get training zones based on that. After conducting this test, you can start training and monitoring you training intensities from muscle loading. In order to get reliable results, the test should be conducted at nearly flat terrain since heavy up- and downhills affect the muscle loading. You can conduct the test with running, cycling, skiing, skating, hiking etc. but you have to remember that MFT and training zones are applicable to that sport type only.
Start with warm-up for 15-20 minutes with comfortable constant exercise intensity so that your heart rate is around 0.67 * from you Max HR. If you are a recreational and will do a running test, your warm-up intensity can well be brisk walking. Warm-up intensity should not make you sweat strongly or breath heavily. After warm-up, increase your training intensity. If you are a recreational, your target HR is 0.85 * from your Max HR. If you are an athlete, your target intensity is a bit higher, 0.9 * your Max HR. Keep exercising in that constant intensity for 10 minutes so that your HR is inside target
area. Target intensity should make you sweat and your breathing goes heavier but you should feel that you could keep exercising with the same intensity for 20-30 minutes more.
In figure 2 there is an example of General MFT Test warm-up and threshold level HR calculations and in figure 3 about the determined MFT and zones based on it.
Figure 2. Example on calculations for warm-up level and threshold level target HRs during General MFT Test.
Figure 3. Example on measured muscle loads and calculated MFT and exercise intensity zones based on General MFT Test done in this case with running. White graph is ML and light red line is HR.
Incremental running test 6 x 1000 m
Incremental running test is a heart rate guided running test targeted especially for athletes to determine muscle fatigue threshold and get training zones based on that. Conduct the test if you want to get MFT and training zones for running training. In the test there are six intensity levels, 1000 m each, from very light intensity until maximal running. Heart rate, muscle loading and running speed increase progressively from one level to another. If you are a recreational, you can shorten the running distance to 800m.
In order to get reliable results, the test should be conducted at sports track either in sports hall or outdoors during calm windless day. Figure 4 presents the target HR intensities based on known or estimated max HR.
Figure 4. Target intensities for 6 x 1000 m Incremental Running Test. Target HRs are affected by max HR. Start with speeding up mildly to raise your HR to Level 1 target HR (± 5 bpm) and keep up that constant light loading level for 1000 m. This first phase is the warm-up so the actual test starts from level 2. Continue likewise without stopping until you reach Level 6. During Level 6 you do not need to check your HR. The aim is to run Level 6 with increasing speed so that the final stage is run at maximal effort. Figure 5 presents typical muscle load curves for this test as well as determined MFT and zones.
Figure 5. Muscle load curves during 6 x 1000 m Incremental Running Test. First two intensities are very light. Thereafter intensity increases and MFT is reached at level 5. Last level 6 shows huge muscle load potentiation because of accelerative all out sprinting and cumulative fatigue. NOTE! This specific data includes short stops between intensities to collect blood samples during our validation process.
Incremental cycling test until exhaustion
Incremental cycling test is a resistance (power) guided exercise test targeted especially for athletes to determine muscle fatigue threshold and get cycling training zones based on that. Conduct the test if you want to get training zones specifically for cycling training. Test begins with very light intensity and resistance increases every 2 min until exhaustion.
You need power meter or bike trainer to detect cycling resistance (power, W). It is highly recommended to use electronic trainer where test protocol can be preprogrammed and which can control resistance regardless of your cadence or gearing selection. If that is not possible, increase power manually and keep the cadence constant. There are separate test protocols for male and female athletes in order to ensure appropriate test duration (12-30 min). Figure 6 summarizes the cycling test
protocols. Start your bike trainer’s test protocol and concentrate on pedalling as easily as possible with your constant preferred pedalling frequency (70-105 rpm). Continue pedalling as long as you can. Figure 7 presents typical muscle activation data during Incremental cycling test as well as determined MFT and zones.
Figure 6. Test protocols for Incremental cycling test for men and women.
Figure 7. Muscle loads, MFT and exercise zones during Incremental cycling test until exhaustion. First six intensities are mild and muscle activation increases very little despite of increasing cycling power. MFT is reached at level 9. Final level 12 shows highly increased muscle load due to cumulative fatigue and maximal exertion.
As can be seen, the muscle load based training zones offer precise and effective option to training and totally new perspective to set exercise intensities. Being close to working muscles, fatigue accumulation is spotted early and accurately. In our next posts we’ll present practical examples how the zones are used in various disciplines and training targets.
Pekka Tolvanen, M.Sc. (Physics), Product Manager, Founder of Myontec
Merja Hoffrén-Mikkola, PhD (biomechanics), Content Developer, Myontec